A roadside blast struck a NATO convoy in southern Afghanistan and wounded four alliance soldiers Saturday, while fighting in three separate regions of the country left more than 100 militants dead, officials said.

Violence is rising rapidly in Afghanistan five years into the U.S.-led effort to defeat the Taliban,

The NATO convoy was attacked west of Kandahar city, and the four wounded soldiers were taken to a nearby military hospital, said Maj. John Thomas, a NATO spokesman.

Qari Yousef Ahmadi, a purported Taliban spokesman, said a suicide bomber had attacked the convoy.

An Associated Press reporter at the scene said the wounded soldiers were Canadian, but that could not be immediately confirmed.

The attack happened a day after officials said fierce fighting in three separate regions of Afghanistan killed more than 100 militants.

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Shalizai Dedar, governor of northeastern Kunar province, said villagers accused foreign troops of killing dozens of civilians in airstrikes Friday. He said about 60 militants died in the battle but he could not confirm the reports of civilian deaths.

U.S.-led coalition and NATO spokesmen on Friday emphasized that ground commanders had evaluated the terrain in Kunar province to prevent civilian casualties, but Dedar said villagers had reported that an initial airstrike killed 10 civilians — and that a second killed about 30 people who were trying to bury the dead.

Abdul Sabur Allayar, the provincial deputy police chief, said Saturday that 25 civilians and 20 militants were killed in clashes over three days.

The fighting — in the south, west and northeast — follows a trend of sharply rising bloodshed over the past five weeks, among the deadliest periods since the U.S.-led invasion in 2001.

Insurgency-related violence in June alone killed more than 1,000 people, including 200 civilians, according to an AP count based on information from Western and Afghan officials.

More than 3,100 people have been killed in Afghanistan this year, according to the AP tally. About 4,000 people died in the violence in all of last year.

U.S. and NATO officials have said Taliban militants threaten villagers into claiming that attacks killed civilians.

"There were some number of insurgents that were killed. We have no reason to believe that any civilians were killed at this time," NATO's Thomas said. He said soldiers called in airstrikes on "positively identified enemy firing positions" in a remote area.

Civilian deaths have been a growing problem for international forces in Afghanistan, threatening to derail support for the Western mission. President Hamid Karzai has repeatedly implored forces to try preventing such deaths.

Both a U.N. and the AP count of civilian deaths this year show that U.S. and NATO forces have caused more civilian deaths this year than Taliban fighters have.

In the south, militants attacked two police vehicles with gunfire and rocket propelled grenades overnight Thursday, and U.S.-led coalition and Afghan forces responded with artillery fire and airstrikes in what the coalition described as a "sparsely populated area" in Uruzgan province.

Gen. Zahir Azimi said 33 Taliban fighters were killed. The coalition reported "no indications" of civilian casualties, and said no coalition or Afghan forces were killed or wounded.

In Farah, a western province bordering Iran that has seen little violence until this year, insurgents attacked an Afghan security patrol from fortified positions and wounded five Afghan soldiers, the coalition said.

Afghan and coalition forces, using gunfire and airstrikes, killed "over 30" insurgents, it said. The coalition also said a ground commander "carefully evaluated risk of collateral damage" before firing.

The latest NATO casualties have raised the number of foreign soldiers killed this year to at least 105.

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